The objectives of the study are to evaluate the clinical activity and safety of nelfinavir administered in combination with ZDV and 3TC in HIV-positive subjects who have received less than one month of ZDV or no prior antiretroviral and HIV RNA titers 315,000 copies/ml. The primary endpoints are change from baseline in CD4 cell counts and quantitative plasma RNA titer. In addition the protocol will attempt to assess the potential for viral resistance by measuring changes in genotype, phenotype and viral sensitivity.